An announcement cites both O’Malley’s role as chairman of the Democratic Governors Association and his championing this year of Maryland’s same-sex marriage law, which is likely to be petitioned to the ballot in November.

O’Malley’s national profile has been on the rise during his nearly year and a half as chairman of the DGA — though he has drawn some flak from lawmakers back home who accuse him of not paying enough attention to Maryland legislative matters.

In recent months, O’Malley — who has brushed off speculation about ambitions beyond Maryland — has become a regular on Sunday talk shows and made other appearances at Democratic gatherings around the country.

His trip to New Hampshire is his second this year to an early presidential nominating state. In January, he appeared at a national party news conference in South Carolina shortly before the Republican primary in that state.

O’Malley appeared at the same event in New Hampshire five years ago, as a stand-in for for Hillary Rodham Clinton, whom he had endorsed in the 2008 Democratic presidential primaries.

John Wagner is a national reporter who leads The Post's new breaking political news team. He previously covered the Trump White House. During the 2016 presidential election, he focused on the Democratic campaigns of Hillary Clinton, Bernie Sanders and Martin O’Malley. He also chronicled Maryland government for more than a decade.